"Did I already take it?"
The most common daily worry on any medication is not forgetting — it is not being sure. Doses group by time slot on the Today screen and a finished slot collapses to "2 completed", so the answer is one glance instead of one guess. Long-press the notification on the lock screen and tap Taken to log without unlocking. Several doses at the same time go in with a single Take all. Tapped one by mistake? Long-press the card and undo it.